Fix MD040 warnings

The following warnings are generated by using markdownlint analysis:
```
MD040/fenced-code-language Fenced code blocks should have a language specified [Context: "```"]
```
Refer to markdown-lint [1] to fix MD040
[1]: https://github.com/updownpress/markdown-lint/blob/master/rules/040-fenced-code-language.md

Signed-off-by: George Liu <liuxiwei@ieisystem.com>
Change-Id: Ib455fe1ac0113d54115f8a15ecb6cd4bfcc07681
diff --git a/docs/README.md b/docs/README.md
index 3fe0ce5..6a3532a 100644
--- a/docs/README.md
+++ b/docs/README.md
@@ -1,8 +1,8 @@
 ## To Build
 
-```
 To build this package, do the following steps:
 
+```sh
     1. meson build
     2. ninja -C build
 ```
@@ -11,7 +11,7 @@
 
 #### Configure LDAP
 
-```
+```sh
 curl -c cjar -b cjar -k -H "Content-Type: application/json" -X POST -d '{"data":[false,"ldap://<ldap://<LDAP server ip/hostname>/", "<bindDN>", "<baseDN>","<bindDNPassword>","<searchScope>","<serverType>"]}''  https://$BMC_IP/xyz/openbmc_project/user/ldap/action/CreateConfig
 
 ```
@@ -26,26 +26,26 @@
 
 #### Upload LDAP Client Certificate
 
-```
+```sh
 curl -c cjar -b cjar -k -H "Content-Type: application/octet-stream"
      -X PUT -T <FILE> https://<BMC_IP>/xyz/openbmc_project/certs/client/ldap
 ```
 
 #### Upload CA Certificate
 
-```
+```sh
 curl -c cjar -b cjar -k -H "Content-Type: application/octet-stream"
      -X PUT -T <FILE> https://<BMC_IP>/xyz/openbmc_project/certs/authority/truststore
 ```
 
 #### Clear LDAP Config
 
-```
+```sh
 curl -b cjar -k -H "Content-Type: application/json" -X POST -d '{"data":[]}' https://$BMC_IP/xyz/openbmc_project/user/ldap/config/action/delete
 ```
 
 #### Get LDAP Config
 
-```
+```sh
 curl -b cjar -k https://$BMC_IP/xyz/openbmc_project/user/ldap/enumerate
 ```